From 5ccc6e5ec8a433f68bfeb17e8dcedec5b62a36a9 Mon Sep 17 00:00:00 2001
From: Nathan Reiner <nathan@nathanreiner.xyz>
Date: Wed, 17 Jan 2024 18:24:21 +0100
Subject: First sketch of matheval

---
 src/main.rs | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 src/main.rs

(limited to 'src/main.rs')

diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..313769f
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,58 @@
+pub mod context;
+pub mod expression;
+pub mod function;
+pub mod operation;
+pub mod string;
+
+use std::collections::HashMap;
+
+use expression::Expression;
+use function::Function;
+use operation::Operation;
+
+use crate::context::Context;
+
+fn add(a: f64, b: f64) -> f64 {
+    a + b
+}
+
+fn mul(a: f64, b: f64) -> f64 {
+    a * b
+}
+
+fn div(a: f64, b: f64) -> f64 {
+    a / b
+}
+
+fn pow(a: f64, b: f64) -> f64 {
+    a.powf(b)
+}
+
+fn sqrt(a: f64) -> f64 {
+    a.sqrt()
+}
+
+impl<T> Function for T
+where
+    T: Fn(f64) -> f64,
+{
+    fn eval(&self, args: function::FunctionArgument) -> f64 {
+        self(args.get(0))
+    }
+}
+
+fn main() {
+    let expr = "(2 + (3 + 10) * (3 + 10)) * 2";
+
+    let mut funcs : HashMap<String, Box<dyn Function>> = HashMap::new();
+    funcs.insert("sqrt".to_string(), Box::new(&sqrt));
+    let ctx: Context = Context::new()
+        .with_operations(opvec![('+', &add), ('*', &mul), ('/', &div), ('^', &pow)])
+        .with_functions(funcs);
+    let value = Expression::from_string(expr);
+
+    match value.evaluate(&ctx) {
+        Ok(res) => println!("{} = {}", expr, res),
+        Err(err) => println!("Error: {}", err),
+    }
+}
-- 
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